I don't know about Windows versions of the games, but the Mac versions of several of the Spiderweb games are having problems opening the installers on the CDs on Intel Macs (I think OS X 10.6.x may be the culprit). This is only a problem if you bought the CD versions of the games.

Jeff Vogel posted a supposed fix on the website, but it didn't work for me. He then suggested I just download the demos from the spiderwebsoftware.com site and he would gladly send me registration codes for them. The problem with this is that the reason I bought the CD versions (at extra cost) in the first place was that I do not like the "registration codes" since they are only good for one install and then they don't work. requesting another from Spiderweb solves the problem, but not if Spiderweb stops supporting the games for whatever reason. Then I would just have demos with no way to unlock them.

So, here is a fix that works if you have another, older Mac. Install the games on your older Mac. Then go to the Preferences folder (users/<username>/Library/Preferences in OS X, OR System Folder/Preferences under OS 9) and copy all the Spiderweb game preference files to a backup folder on your desktop or wherever. Then copy this folder to a flash drive or disk and put it in your Intel Mac. Copy the Spiderweb preference files to users/<username>/Library/Preferences in your Intel Mac, and the games should now be registered there. All you have to do is download the latest demos from the Spiderwebsoftware.com site and they should work fine.

I would strongly suggest making a back-up disk with the latest demo installers and all the preferences files (from the fill-game CDs, NOT the demo preference files!) for future use.